Hello, I have a question about the creation a guard drake.

The ritual, which takes several days, requires 10 pounds of fresh dragon scales (donated by the dragon allied with the group), a large amount of fresh meat,
and an iron cauldron. When the process is complete, a halfling-sized egg emerges from the cauldron and is ready to hatch within a few hours.

Did the scales from a dragon give voluntarily to have a successful ritual ? Or with scales from a dead or injured dragon, or scales in a treasure, is it right also ?

Thanks for your future help.

paragraph directly before it states that they are gifts from dragons and that the dragon must be involved in the ritual:

Gifts from Dragons. The ritual to create a guard drake was originally devised by the cult of Tiamat, but has spread to other groups that are skilled in arcana and associated with dragons. The cooperation of a dragon is necessary for the ritual to succeed, and a dragon typically provides its help when it wants to reward its allies or worshipers with a valuable servant.